What is SAObjects.framework? - ios

I've added SACalendar custom classes to my Xcode project and now when I run the app I get this log:
objc[3230]: Class SACalendar is implemented in both /System/Library/PrivateFrameworks/SAObjects.framework/SAObjects and /private/var/mobile/Containers/Bundle/Application/XXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXX/MyApp.app/MyApp. One of the two will be used. Which one is undefined.
What is such SAObjects.framework? Would this conflict cause actually a problem?
Thanks

As the message says, it is a private framework (meaning that it contains stuff that does not have a public API). I think this one started shipping with iOS7.
IMO, Apple should do a better job naming their private classes, and prefix them with an underscore or something, but they don't. That framework even has classes with no specific prefix (like AceObject).
Since ObjectiveC does not have namespace support, you can (and will) get name collisions. All you can do is rename your classes that clash with system frameworks... and hope your prefix of choice is not chosen by some other framework shipped with the system.
I would advise you to rename your SACalendar class, and any other classes that cause a conflict.
If you want to know the contents of that framework, just load it and use the objc runtime to discover its properties... or use one of the many tools already available (like this one).

It seems to be this: https://github.com/nopshusang/SACalendar
Yes, it is a problem.
However, you get this problem because you and many, many other developers do not read the Objective-C's and Cocoa's naming conventions. There are typically two mistakes:
Prefixes with two letters are reserved for Apple. You are not allowed to use it. I really do not know, why do not respect this. This is the problem in your case.
Prefixes does not denote a subject, but the origin of code. Therefore extending (subclass, category) a class from Cocoa (NS-Prefix) by a third-party developer does not have the prefix NS. But you see it everywhere.
I really do not know, why it is that difficult to accept that simple rules.
Your own classes should use three letter prefixes. These might relate to a combination of your company name and your app name, or even a specific component within your app. As an example, if your company were called Whispering Oak, and you were developing a game called Zebra Surprise, you might choose WZS or WOZ as your class prefix.

As for what SAObjects.framework actually does, according to https://www.theiphonewiki.com/wiki/Siri, it contains "Resources for Siri objects".

Related

Good or bad idea to prefix all classes with same abbreviation?

So in practically all my programs I wrote I always prefixed every class I created with the same abbreviation that was in relation to the program. So for instance say I wrote an app called GasStationDeluxe. I would make a class called GSDGasStation or GSDGasPump etc. Now I always thought that is a good idea because it would group together all thelse classes I created in intellisense to make it easier for me and other programmers to find the classes I created.
Yet, I'm reading a book called "Clean Code: A Handbook of agIle software craftsmanship" and I just read a part in a chapter where it says it's not a good idea to do that becasue auto complete will bring you back a list of tons of classes. So who else codes this way? Do you think it's a good or bad idea to code with the same prefix before each class? If yes or no, then why?
I have never done this, but you will sometimes see it done in solutions with multiple projects like GSD.App or GSD.Core
I was always that in a class called Customer.cs, you might not want to make the name field CustomeName but just Name as your already in the customer class so what is it adding. I suppose the same is true in your case of classes.
What if you want to reuse your classes elsewhere? I would say from the vast majority of code examples I come across and other peoples code I read, this isn’t common practice.
I suppose really it’s up to you and any team you work with, as long as it’s consistent.
I wonder what .net would look like if Microsoft prefixed everything!

Swift Framework Prefix?

I'm building a Cocoa Touch Framework in Swift to create a UI component like the iOS Messages "To" Token Field.
What should I name the framework?
What should I name the class?
I'm thinking of naming them both the same, but I'm not sure if I should add a prefix.
Some ideas are:
UITokenTextView (standard prefix)
ACTokenTextView (custom prefix)
TokenTextView (no prefix)
I'm considering naming it UITokenTextView, but could that cause conflicts if in the future, Apple introduces a class with the same name?
Also, why not just call it TokenTextView? That is, why has Apple kept the UI class prefix in Swift?
You should better check this document:
Programming with Objective-C
Class Names Must Be Unique Across an Entire App
In Objective-C, there's no namespace support and all globals names (including all class names) exist in a flat global space. And prefixes are used as sort of namespace to make your class name unique. So, Objective-C compatible classes provided by frameworks should have a unique prefix representing your framework.
And please do not miss this description in Apple's doc.
You’ll have noticed that Cocoa and Cocoa Touch class names typically start either with NS or UI. Two-letter prefixes like these are reserved by Apple for use in framework classes.
You should avoid two-letter prefixes, as all such prefixes are considered to be reserved by Apple. Apple may at any time reject apps which uses two-letter prefix frameworks in the future. (I know some frameworks are still using two-letter prefix, I'm not sure Apple would really rejects them.)
(And Apple uses some three-letter prefixes like MTL-, although there are many more two-letter prefixes still available.)
2. What should I name the class?
For Swift only classes, as you like. But better avoid some names which may conflict with members of Swift Standard Library (or any names you think would be imported into usual apps.)
For Objective-C compatible classes, use proper prefix having three letters at least. You should not use UI or AC.
I'm thinking of naming them both the same
You can choose any name you like as a framework name, but you should better make your module name and any existing type names different. Swift is often confused with type names and module names.
I think, if a class has a swift version type, struct or class, it's prefix is dropped, eg: NSData vs Data, or the prefix is kept.
In other way, the Data and NSData are different types, not just drop the NS prefix.

RAML- !include strange behavior

I use this extension for Atom, to design my API, written in RAML.
I think I have a problem here :(I masked title and baseUri, sorry) :
If I follow RAML 1.0 specs, I should put a "!include". Strangely, apiworkbench detects no mistake.
If I do that :
Why didn't this work?
Very good conversations. Indeed the specification should be more clear about that, but the reason why libraries follows a different approach than normal !include is that an include simply adds new nodes to an existing where ever you used the !include keyword. Since it really is a simple "add" operation, it does not cover up for any cyclic dependencies.
Libraries are very much different and the use of namespaces (uses) are very much different. The purpose of libraries is to create a common shareable group of assets/definitions of best practices that people also use to create their own libraries or other definitions on top. Cyclic dependencies are inevitable. For that, the RAML workgroup had to come up with a different mechanism than what you have with !include. Hence, for libraries you should always use:
uses
lib: mylib.raml
Hope that explains the rationality behind it, but please let me know if you have more questions.
No, for libraries you must NOT use the include keyword.
It seems the specification is not very clear about this or at least I could not find it clearly specified anywhere. Thus raising an issue about this would be a good idea.
But if you check the examples in the specification you will see that when using libraries (with the "uses" keyword) the "!include" is omitted.

Naming conflict in objective c framework [duplicate]

Objective-C has no namespaces; it's much like C, everything is within one global namespace. Common practice is to prefix classes with initials, e.g. if you are working at IBM, you could prefix them with "IBM"; if you work for Microsoft, you could use "MS"; and so on. Sometimes the initials refer to the project, e.g. Adium prefixes classes with "AI" (as there is no company behind it of that you could take the initials). Apple prefixes classes with NS and says this prefix is reserved for Apple only.
So far so well. But appending 2 to 4 letters to a class name in front is a very, very limited namespace. E.g. MS or AI could have an entirely different meanings (AI could be Artificial Intelligence for example) and some other developer might decide to use them and create an equally named class. Bang, namespace collision.
Okay, if this is a collision between one of your own classes and one of an external framework you are using, you can easily change the naming of your class, no big deal. But what if you use two external frameworks, both frameworks that you don't have the source to and that you can't change? Your application links with both of them and you get name conflicts. How would you go about solving these? What is the best way to work around them in such a way that you can still use both classes?
In C you can work around these by not linking directly to the library, instead you load the library at runtime, using dlopen(), then find the symbol you are looking for using dlsym() and assign it to a global symbol (that you can name any way you like) and then access it through this global symbol. E.g. if you have a conflict because some C library has a function named open(), you could define a variable named myOpen and have it point to the open() function of the library, thus when you want to use the system open(), you just use open() and when you want to use the other one, you access it via the myOpen identifier.
Is something similar possible in Objective-C and if not, is there any other clever, tricky solution you can use resolve namespace conflicts? Any ideas?
Update:
Just to clarify this: answers that suggest how to avoid namespace collisions in advance or how to create a better namespace are certainly welcome; however, I will not accept them as the answer since they don't solve my problem. I have two libraries and their class names collide. I can't change them; I don't have the source of either one. The collision is already there and tips on how it could have been avoided in advance won't help anymore. I can forward them to the developers of these frameworks and hope they choose a better namespace in the future, but for the time being I'm searching a solution to work with the frameworks right now within a single application. Any solutions to make this possible?
Prefixing your classes with a unique prefix is fundamentally the only option but there are several ways to make this less onerous and ugly. There is a long discussion of options here. My favorite is the #compatibility_alias Objective-C compiler directive (described here). You can use #compatibility_alias to "rename" a class, allowing you to name your class using FQDN or some such prefix:
#interface COM_WHATEVER_ClassName : NSObject
#end
#compatibility_alias ClassName COM_WHATEVER_ClassName
// now ClassName is an alias for COM_WHATEVER_ClassName
#implementation ClassName //OK
//blah
#end
ClassName *myClass; //OK
As part of a complete strategy, you could prefix all your classes with a unique prefix such as the FQDN and then create a header with all the #compatibility_alias (I would imagine you could auto-generate said header).
The downside of prefixing like this is that you have to enter the true class name (e.g. COM_WHATEVER_ClassName above) in anything that needs the class name from a string besides the compiler. Notably, #compatibility_alias is a compiler directive, not a runtime function so NSClassFromString(ClassName) will fail (return nil)--you'll have to use NSClassFromString(COM_WHATERVER_ClassName). You can use ibtool via build phase to modify class names in an Interface Builder nib/xib so that you don't have to write the full COM_WHATEVER_... in Interface Builder.
Final caveat: because this is a compiler directive (and an obscure one at that), it may not be portable across compilers. In particular, I don't know if it works with the Clang frontend from the LLVM project, though it should work with LLVM-GCC (LLVM using the GCC frontend).
If you do not need to use classes from both frameworks at the same time, and you are targeting platforms which support NSBundle unloading (OS X 10.4 or later, no GNUStep support), and performance really isn't an issue for you, I believe that you could load one framework every time you need to use a class from it, and then unload it and load the other one when you need to use the other framework.
My initial idea was to use NSBundle to load one of the frameworks, then copy or rename the classes inside that framework, and then load the other framework. There are two problems with this. First, I couldn't find a function to copy the data pointed to rename or copy a class, and any other classes in that first framework which reference the renamed class would now reference the class from the other framework.
You wouldn't need to copy or rename a class if there were a way to copy the data pointed to by an IMP. You could create a new class and then copy over ivars, methods, properties and categories. Much more work, but it is possible. However, you would still have a problem with the other classes in the framework referencing the wrong class.
EDIT: The fundamental difference between the C and Objective-C runtimes is, as I understand it, when libraries are loaded, the functions in those libraries contain pointers to any symbols they reference, whereas in Objective-C, they contain string representations of the names of thsoe symbols. Thus, in your example, you can use dlsym to get the symbol's address in memory and attach it to another symbol. The other code in the library still works because you're not changing the address of the original symbol. Objective-C uses a lookup table to map class names to addresses, and it's a 1-1 mapping, so you can't have two classes with the same name. Thus, to load both classes, one of them must have their name changed. However, when other classes need to access one of the classes with that name, they will ask the lookup table for its address, and the lookup table will never return the address of the renamed class given the original class's name.
Several people have already shared some tricky and clever code that might help solve the problem. Some of the suggestions may work, but all of them are less than ideal, and some of them are downright nasty to implement. (Sometimes ugly hacks are unavoidable, but I try to avoid them whenever I can.) From a practical standpoint, here are my suggestions.
In any case, inform the developers of both frameworks of the conflict, and make it clear that their failure to avoid and/or deal with it is causing you real business problems, which could translate into lost business revenue if unresolved. Emphasize that while resolving existing conflicts on a per-class basis is a less intrusive fix, changing their prefix entirely (or using one if they're not currently, and shame on them!) is the best way to ensure that they won't see the same problem again.
If the naming conflicts are limited to a reasonably small set of classes, see if you can work around just those classes, especially if one of the conflicting classes isn't being used by your code, directly or indirectly. If so, see whether the vendor will provide a custom version of the framework that doesn't include the conflicting classes. If not, be frank about the fact that their inflexibility is reducing your ROI from using their framework. Don't feel bad about being pushy within reason — the customer is always right. ;-)
If one framework is more "dispensable", you might consider replacing it with another framework (or combination of code), either third-party or homebrew. (The latter is the undesirable worst-case, since it will certainly incur additional business costs, both for development and maintenance.) If you do, inform the vendor of that framework exactly why you decided to not use their framework.
If both frameworks are deemed equally indispensable to your application, explore ways to factor out usage of one of them to one or more separate processes, perhaps communicating via DO as Louis Gerbarg suggested. Depending on the degree of communication, this may not be as bad as you might expect. Several programs (including QuickTime, I believe) use this approach to provide more granular security provided by using Seatbelt sandbox profiles in Leopard, such that only a specific subset of your code is permitted to perform critical or sensitive operations. Performance will be a tradeoff, but may be your only option
I'm guessing that licensing fees, terms, and durations may prevent instant action on any of these points. Hopefully you'll be able to resolve the conflict as soon as possible. Good luck!
This is gross, but you could use distributed objects in order to keep one of the classes only in a subordinate programs address and RPC to it. That will get messy if you are passing a ton of stuff back and forth (and may not be possible if both class are directly manipulating views, etc).
There are other potential solutions, but a lot of them depend on the exact situation. In particular, are you using the modern or legacy runtimes, are you fat or single architecture, 32 or 64 bit, what OS releases are you targeting, are you dynamically linking, statically linking, or do you have a choice, and is it potentially okay to do something that might require maintenance for new software updates.
If you are really desperate, what you could do is:
Not link against one of the libraries directly
Implement an alternate version of the objc runtime routines that changes the name at load time (checkout the objc4 project, what exactly you need to do depends on a number of the questions I asked above, but it should be possible no matter what the answers are).
Use something like mach_override to inject your new implementation
Load the new library using normal methods, it will go through the patched linker routine and get its className changed
The above is going to be pretty labor intensive, and if you need to implement it against multiple archs and different runtime versions it will be very unpleasant, but it can definitely be made to work.
Have you considered using the runtime functions (/usr/include/objc/runtime.h) to clone one of the conflicting classes to a non-colliding class, and then loading the colliding class framework? (this would require the colliding frameworks to be loaded at different times to work.)
You can inspect the classes ivars, methods (with names and implementation addresses) and names with the runtime, and create your own as well dynamically to have the same ivar layout, methods names/implementation addresses, and only differ by name (to avoid the collision)
Desperate situations call for desperate measures. Have you considered hacking the object code (or library file) of one of the libraries, changing the colliding symbol to an alternative name - of the same length but a different spelling (but, recommendation, the same length of name)? Inherently nasty.
It isn't clear if your code is directly calling the two functions with the same name but different implementations or whether the conflict is indirect (nor is it clear whether it makes any difference). However, there's at least an outside chance that renaming would work. It might be an idea, too, to minimize the difference in the spellings, so that if the symbols are in a sorted order in a table, the renaming doesn't move things out of order. Things like binary search get upset if the array they're searching isn't in sorted order as expected.
#compatibility_alias will be able to solve class namespace conflicts, e.g.
#compatibility_alias NewAliasClass OriginalClass;
However, this will not resolve any of the enums, typedefs, or protocol namespace collisions. Furthermore, it does not play well with #class forward decls of the original class. Since most frameworks will come with these non-class things like typedefs, you would likely not be able to fix the namespacing problem with just compatibility_alias.
I looked at a similar problem to yours, but I had access to source and was building the frameworks.
The best solution I found for this was using #compatibility_alias conditionally with #defines to support the enums/typedefs/protocols/etc. You can do this conditionally on the compile unit for the header in question to minimize risk of expanding stuff in the other colliding framework.
It seems that the issue is that you can't reference headers files from both systems in the same translation unit (source file). If you create objective-c wrappers around the libraries (making them more usable in the process), and only #include the headers for each library in the implementation of the wrapper classes, that would effectively separate name collisions.
I don't have enough experience with this in objective-c (just getting started), but I believe that is what I would do in C.
Prefixing the files is the simplest solution I am aware of.
Cocoadev has a namespace page which is a community effort to avoid namespace collisions.
Feel free to add your own to this list, I believe that is what it is for.
http://www.cocoadev.com/index.pl?ChooseYourOwnPrefix
If you have a collision, I would suggest you think hard about how you might refactor one of the frameworks out of your application. Having a collision suggests that the two are doing similar things as it is, and you likely could get around using an extra framework simply by refactoring your application. Not only would this solve your namespace problem, but it would make your code more robust, easier to maintain, and more efficient.
Over a more technical solution, if I were in your position this would be my choice.
If the collision is only at the static link level then you can choose which library is used to resolve symbols:
cc foo.o -ldog bar.o -lcat
If foo.o and bar.o both reference the symbol rat then libdog will resolve foo.o's rat and libcat will resolve bar.o's rat.
Just a thought.. not tested or proven and could be way of the mark but in have you considered writing an adapter for the class's you use from the simpler of the frameworks.. or at least their interfaces?
If you were to write a wrapper around the simpler of the frameworks (or the one who's interfaces you access the least) would it not be possible to compile that wrapper into a library. Given the library is precompiled and only its headers need be distributed, You'd be effectively hiding the underlying framework and would be free to combine it with the second framework with clashing.
I appreciate of course that there are likely to be times when you need to use class's from both frameworks at the same time however, you could provide factories for further class adapters of that framework. On the back of that point I guess you'd need a bit of refactoring to extract out the interfaces you are using from both frameworks which should provide a nice starting point for you to build your wrapper.
You could build upon the library as you and when you need further functionality from the wrapped library, and simply recompile when you it changes.
Again, in no way proven but felt like adding a perspective. hope it helps :)
If you have two frameworks that have the same function name, you could try dynamically loading the frameworks. It'll be inelegant, but possible. How to do it with Objective-C classes, I don't know. I'm guessing the NSBundle class will have methods that'll load a specific class.

Where to put Constants.swift?

I'm a newbie to Swift and iOS programming in general, and I'm currently getting my hands dirty building a Swift app. I have encountered this problem of where to put the Constants.swift file (which basically stores the constants used by the app), and the confusion is mainly caused by the MVC logic. I have two options that I deem somewhat reasonable.
Put Constants.swift outside of the MVC framework, so that it does not belong to any particular party. Rationale: this way it could be conveniently referenced by all the components.
Put Constants.swift in the controller. Rationale: Controller is application-specific, and so is Constants.swift. Model and View are generic and hence should not be used to store constants.
But I don't know which of the two above I should use, or if there are any better options. What do you all think?
I think you should separate the constants in the classes that have to do with them and access them like:
Configurations.Constants.width or Car.Constant.speed
You can use structs with static properties to store them.
Don't know if that is your case, and depends on the constants, but it is not common to have one file with ALL the constants of the program, or one file with constants that need to be accessed from all the other components, this could indicate a design problem. If you store them close to or in the classes related to them, you won't have a problem with Cocoa's MVC.

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